Soil nematodes: determinants of microplastic-induced changes of the soil microbiome

Microplastics are the source of widespread pollution in marine and soil ecosystems, but the impacts of microplastics on the hotspot of biodiversity – soil – remain largely unexplored.  
We tested how different microplastic types (LDPE, representing >48% of agricultural plastics; PBAT, the dominant bioplastic; starch-based plastics, an emerging biodegradable bioplastic in farm use) affect bacteria and nematodes. We conducted this manipulative experiment as we were interested in seeing if the presence of nematodes alters microplastics' impact on soil bacteria.
We found that microplastics affect the soil microbiome more than previously thought, with the peculiar finding that nematodes amplified microplastics' effects on soil bacterial diversity. In the presence of nematodes, all microplastic types changed bacterial communities compared to the control! Therefore, we conclude that commonly performed ecotoxicological studies that focus on a single species or biological group (such as bacteria) might miss patterns that are actually happening in more realistic conditions in soil, which calls for more complexity in compound evaluation.